Chap. V. TWO FORMS OF UAKAPJ. 313 



forests lying opposite to the mouth of the river which 

 leads to Fonteboa, and ranges thence to the banks of 

 the TTati-parana, the most westerly channel of the 

 Japura, situated near Tunantins. Beyond that point to 

 the west there is no trace of either the red or the white 

 form, nor of any other allied species. Neither do they 

 pass to the eastward of the main mouth of the Japura, 

 or to the south shore of the Solimoens. How far they 

 range northwards along the banks of the Japura, I 

 could not precisely ascertain ; Senhor Chrysostomo, 

 however, assured me that at 180 miles from the mouth 

 of this river, neither white nor red Uakari is found, but 

 that a third, black-faced and gray-haired species, takes 

 their place. I saw two adult individuals of Brachyurus 

 rubicundus at Ega, and a young one at Fonteboa ; but 

 was unable to obtain specimens myself, as the forests 

 were inundated at the time I visited their locality. I 

 was surprised to find the hair of the young animal 

 much paler in colour than that of the adults, it being of 

 a sandy and not of a brownish-red hue, and consequently 

 did not differ very much from that of the white species ; 

 the two forms, therefore, are less distinct from each 

 other in their young than in their adult states. The 

 fact of the range of these singular monkeys being 

 so curiously limited as here described, cannot be said to 

 be established until the country lying between the 

 northern shore of the Solimoens and New Granada be 

 well explored, but there can be no doubt of the separa- 

 tion of the two forms in the Delta lands of the Japura, 

 and this is a most instructive fact in the geographical 

 distribution of animals. 



